In many conventional vehicles, air springs replace a vehicle's leaf or coil springs and they accompany the existing shock absorbers on a motor vehicle. The purpose of the air springs is to support the vehicle body on the vehicle suspension and the purpose of the shock absorbers is to dampen the relative movement between the vehicle body and the vehicle suspension. As such, air springs typically utilize the elasticity of air under compression to support the vehicle load instead of the elasticity of metal under elastic deformation as is the case in coil or leaf springs. Typically, air is contained in a chamber and the air is compressed by the vehicle load. The air's compression is what provides the additional spring action and support for the vehicle. Accordingly, when a heavy load on the vehicle is present, the air pressure in the chamber of the air spring is greater than when a smaller load is applied thereto.
When a heavy load is applied, it is desirable for the vehicle's shock absorbers to have more firm damping characteristics than when a light load is applied. However, as the damping characteristics of the conventional shock absorber are based primarily on internal characteristics of the shock absorber itself, it does not have the ability to adjust for this load variation. The present invention was developed in light of these and other drawbacks.